Papers by Author: Ying Xue Yao

Abstract: Virtual assembly based on the virtual reality gives a low-cost and rapid prototyping method for products’ assembly, and tolerances have become a key technique of information integration in CAD/CAM. It will be a new task about how to integrate tolerances into virtual assembly. A toleranced product model based on the virtual reality is constructed for the virtual assembly, and the essential data is saved and managed in database. Model transform interface software is developed, which is a special software that users can get the essential data without any users’ acting. The geometric model of products is constructed in the virtual reality, and the method of getting assembly information, dimensions, and tolerances is proposed. A toleranced product modeling system based on the virtual reality is developed, and the using of tolerances is discussed by an example.

Abstract: Balance precision of gyroscope rotor influences its performance directly. Aiming at the special gyroscope with a spherical cavity mentioned in this paper, a static balance method is proposed. This method can determine not only radial direction but also axial direction relative position between the mass center of rotor and the centroid of rotor’s outer outline. Combined with outer outline location, which can determine the relative position and direction between the mass center of rotor and the centroid of rotor’s outer outline, the relative position and direction between the centroid of spherical cavity and the centroid of outer outline can be determined, and we will know the position of removal amount.

Abstract: It is an important performance for gyroscopes to read out the angle information of the gyroscope rotor accurately. There are few methods for measuring the deflection angle of gyroscopes, and they are only fit for the special rotors. A new method based on laser triangulation with position sensitive device (PSD), and the calculation theory of measuring the deflection angle are presented in this paper, which is designed for measuring the deflection angle of a new type gyroscope rotor, and can improve the precision of measuring by several reflections. It indicates by calculation that the method presented in this paper is feasible, and the precision can be improved several times by many reflections, furthermore, the more the number of reflection is, the higher the precision of measurement is improved.

Abstract: In this paper experiments of the face grinding of Al2024/SiCp through the use of electroplated diamond wheel were carried out. The results indicated that high quality processed surface was achieved by face grinding machining, under the experiment conditions of this paper, the surface roughness was between Ra0.185 μm and Ra0.512μm, and the residual stress of processed surface was compressive stress. Grinding parameter had little effect on tangential force and normal force. Axial grinding force increased with the increasing of grinding depth and was stronger than grinding forces in other two directions.

Abstract: Virtual assembly (VA) is an important application for virtual reality (VR) technology in manufacturing industries that can supply an effective solution to actual assembly problem of products. According to the assembly characteristic of large-scale products such as airplane, rocket and satellite, etc, a new interactive VA environment system is constructed, and its architecture and related key techniques are studied. Considering human free activity in the system, a free-walking perception machine is developed. And a stereo projection approach based on a video generator is proposed to enhance real-time interaction and reduce hardware cost. Finally, those key techniques are successfully applied in the process of satellite assembly planning and training.

Abstract: A position-finding method for machining huge workpiece is presented in this paper, and the principle of intelligent position-finding machining system is proposed. Based on automatic determining the position and orientation of the fixed workpiece frame relative to the movable machine-tool frame, the position-finding model is erected and solved by modified Euler angle and Hong-Tan algorithm. The theoretical analysis and simulation examples demonstrate the validity of the proposed method, and the results indicate that the method is suitable for machining huge workpiece in significant scientific projects.

Abstract: Nanoindentation device has the ability to make the load-displacement measurement with sub-nanometer indentation depth sensitivity, and the nanohardness of the material can be achieved by the load-displacement curve. Aiming at the influence law of indenter tip radius to indentation hardness, testing on the hardness of single-crystal silicon were carried out with the new self-designed nanohardness test device based on nanoindentation technique. Two kinds of Berkovich indenter with radius 40nm and 60nm separately were used in this experiment. According to the load-depth curve, the hardness of single-crystal silicon was achieved by Oliver-Pharr method. Experimental results are presented which show that indenter tip radius do influence the hardness, the hardness value increases and the indentation size effect (ISE) becomes obvious with the increasing of tip radius under same indentation depth.

Abstract: Static and dynamic characteristic of carbon nanotube is analyzed by molecular dynamic simulation. Static analysis show that maximum deflection of carbon nanotube appears at 0.033nm distance from free end of cantilever. When the value of driving voltage is less, the flexibility is more important, then the stiffness increase with the voltage increasing, and the collapse structure or hole appear on carbon nanobute. Under low pressure condition, deflection difference on equi-increase of pressure between no damping and damping simulation is larger than that on high pressure. The results of forced vibration indicate that system response consist of transient and steady-state response. With steps of molecular dynamic simulation increasing, transient response disappears gradually, so system response includes only steady-state response, which is simple harmonic vibration with the same frequency as excitation force. These results are in accord with the classical vibration theory. Moreover they will provide theoretic foundation for designing of nanostructure device.

Abstract: The effect of technological parameters on MAO ceramic coating were investigated through the technique of micro-arc oxidation (MAO) on TC4 titanium alloy and. Microstructure and morphology of coatings were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The result shows that electric parameters and compositions of the electrolyte have notable effects on the growth of MAO ceramic coatings. The cathodic and anodic voltage rise gradually with the oxidation time increasing. The growth rate of ceramic coating is fast at the beginning, and then turns slowly. The ceramic coatings can be divided into three layers from interior to exterior, such as the transition layer, the dense layer and the porous layer. The coating is mainly composed of rutile and anatase and combined with the substrate firmly. The ceramic coating’s composition in inner and outer layers appears quite different. The ceramic coating on titanium alloy is of excellent performance on anti-attrition and anti-corrosion.

Abstract: For rigid rotor that widely applied in gyroscopes, high precision dynamic balance is very important. The paper introduces a dynamic balance method for drum-shape gyroscope rotor: the rotor is supported by gas bearing; detecting the displacement of three points on the drum-shape rotor’s end-plane, obtaining its normal direction. Then according to geometrical relation of geometric axis and polar inertia axis, the dynamic trace of the rotor can be obtained, and the rotor’s mass imbalance is calculated. Experiment result shows that the method has high balance accuracy, particularly suit for high-speed gyroscope rotor whose mass imbalance is small.